Bertha is a city in Todd County, Minnesota, United States. The population was 497 at the 2010 census.
According to the United States Census Bureau, the city has a total area of 1.0 square miles (2.7 km²), all of it land.
As of the census of 2000, there were 470 people, 211 households, and 128 families residing in the city. The population density was 458.2 people per square mile (176.2/km²). There were 228 housing units at an average density of 222.3 per square mile (85.5/km²). The racial makeup of the city was 98.72% White, 0.21% Native American, and 1.06% from two or more races. Hispanic or Latino of any race were 0.21% of the population.